Projectile



June 17, 1947.

H. J. NICHOL S PROJECTILE Filed may 7, 1945 Patented June 17, 1947 UNITED STATES PATENT OFFICE 9 Claims.

This invention relates to armor-piercing explosive projectiles. The invention has particular application to minor-calibre projectiles for use against tanks and other light armored structures, and will be described with particular reference to such use, although the principles and elements of the invention are applicable to projectiles of other types.

In my copending application, Serial N 0. 448,291, Projectile, a novel form of armor-piercing projectile, called a booster projectile, was described. In brief, the booster projectile therein described provides a construction of armor-piercing projectile in which a plunger or the base plug is discharged backwards by an explosive shell-filler during impact of the projectile with the target, and the reaction from such discharge augments the forward momentum of the projectile body, thereby increasing the penetrative ability of the projectile.

The present invention provides a construction in which a direct action and two reactions are combined to augment the forward momentum of the projectile body on impact with armor.

In the classical development of armor-piercing projectiles, the design factors which have mainly contributed to the more eflicient penetration of armor are size, weight, form and strength. An additional radical improvement was efiected by the introduction of the armor-piercing cap, but this factor is of secondary importance in antitank projectiles. Finally, the striking velocity, which is primarily a gun factor, is of paramount importance in achieving penetration. But increasing the size and weight of a projectile also means increasing the gun weight by at least one hundred times the increase of the projectile weight, and also materially increases the cost of gun and ammunition, and reduces the rate of fire. Increasing the velocity of the projectile at the gun in order to obtain a greater striking velocity entails a larger and more costly gun, with decreased life of the gun barrel. Accordingly, it appears that the improvement of armor-piercing projectiles along classical lines has reached the gleaner stage, or at least the stage of rapidly diminishing returns. Hence it is evident that the utilization of the explosive force of a charge carried in the projectile to increase the penetrating ability of the projectile according to the present invention is a highly advantageous innovation.

It is accordingly a principal object of the present invention to utilize the power of an explosive shell-charge to increase the armor-piercing properties of projectiles constructed in accordance with the invention.

A further object is to provide a radical improvement in the armor-piercing properties of minor calibre projectiles without radically changing their form nor materially increasing their cost.

A particular object is to provide a projectile of simple construction which is highly efficient in penetrating armor at oblique as well as substantially normal angles of attack.

A further object is to provide a highly efiicient and practical construction for armor-piercing projectiles for attacking tanks, enabling relatively light, fast firing cannon to defeat medium and heavy tanks.

Other objects will appear obvious or will be hereinafter pointed out in the course of the following description.

In the drawings:

Fig. 1 shows a central longitudinal section of a projectile constructed according to the invention;

Fig. 1a shows a transverse cross-section of the projectile shown in Fig. 1, taken at the plane a-a thereof;

Fig. 2 shows in graphic manner a projectile according to the invention in the first stage of penetrating armor; and

Fig. 3 shows in similar manner the same projectile in the second stage of penerating armor.

Referring now to the drawings in detail, and particularly to Fig. 1, the main structural element of the projectile assembly comprises a monoblock body Ill of conventional form and proportions. The body is preferably made of the highest quality alloy steel, as for example chrome-nickel, chrome-vanadium, chrome-molyvbdenum, or similar superior alloy steel. Its impact resisting and armor-piercing properties should be augmented to the utmost by mechanical and heat treatment according to well known practice. The head H of the projectile must be extremely hard, rigid, and tough to prevent breaking up or upsetting on striking the target, but the remainder of the body should be tempered progressively for increasing elasticity and decreasing hardness in well known manner. The head H is preferably of ogival form of the general proportions and shape at the point which have been found in practice to be most effective for armor-piercing. The projectile may be fitted with a cap and windshield if desired, but since these parts are not essential to the invention, the projectile is shown as being fitted only with a molded-on, plastic windshield 30, this construction being considered preferable for small antitank projectiles.

The rear portion or shell l2 of the body is of hollow cylindrical form and is fitted with a rotating band l4, preferably electro-deposited in place as described in my United States Patent No. 2,283,224. With such a band, the customary weakening band groove in the projectile body is eliminated, thus providing a projectile of maximum strength unlikely to fracture, at the band. The electrodeposited band is also superior in uniformity and security, and saves approximately three quarters of the copper required for banding. The shell l2 must be very tough and strong to resist rupture by the expanding gases from the explosive charge as long as possible. Exceptional elasticity is a desideratum for this portion,

since the shell in effect serves as the barrel of a gun, as will appear in the following description. Hence the shell 12 should be constructed to resist internal pressure to the utmost, rather than to be most effectively fragmented .by the explosive charge, as in the usual case of projectiles containing high explosives.

The shell I2 is preferably closed at the base by a screwed-in base detonating fuse 29, or by a screwed-in base plug (not shown), carrying a detonating fuse in the case of larger projectiles. The detonating fuse may be of any suitable design, as for example the simplified fuse for minor calibre projectiles shown in Fig. 1, or that shown in my copending application, Serial No. 304,394, dated November 14, 1939, for larger projectiles. In any case, the fuse body 2! should be very strong and securely held by a well threaded connection so as not to be blown out prematurely by the explosive charge l5.

The fuse should also function with a very slight delay on impact to enable the projectile head to enter the armor before the explosive charge is detonated. In the example shown, the fuse El! comprises the threaded body 2| of rugged proportions provided with an axial cavity containing the firing elements comprising firing means such as ball 22 and detonator '23. The cavity in the fuse body consists of an inner bore 2| housing the ball 22 which is retained therein by cement, solder, or other suitable securing means; and a counter bore housing detonator 23, the latter preferably enclosed in a metal capsule as shown. The fuse cavity is closed by av screwedon cap 2! or other suitable closure.

The ball 22 is held in the rear portion of the bore against dis-lodgement by any except powerful forward acting force. It is therefore in effect an impact percussion element, which functions to explode the detonator shortly after the impact of the projectile with armor.

The explosive charge 15, mounted in the projectile ahead of the fuse 20, is preferably a compressed, high-explosive charge of great strength and high rate of detonation. A piston or hammer 25 of semi-spherical form is suitably mounted near the center of the hollow in the projectile, as for example by a retainer means such as shear ring 26 mounted partly in a groove 25 in the hammer 25 and in a groove I 2' in the wall of shell l2. (See Fig. la.) The purpose of this method of mounting is to suspend the hammer 25 in position with its flat side adjacent the charge IE), but to avoid any blow thereon during handling or the discharge of the gun.

Referring now to the figures in sequence, during handling and discharge in the gun, all the parts of the projectile and fuse assembly remain stationary as shown in Fig. 1. On striking the target T, shown in Figs. 2 and 3 as an armor plate, as the head of the projectile enters the target the force of percussion projects ball 22 forwardly from its seat to strike and explode detonator 23, which instantly detonates the highexplosive charge l5. Thereupon, as illustrated in Fig. 2, the hammer 25 is driven forward with great force to deliver a violent blow to the projectile, driving it forward. At the same time, great pressure is exerted by the explosive gases on fuse 2!] to blow it out rearwardly. The direction of these forces is indicated by the arrows of Fig. 2, and illustrate that there is a powerful forward thrust on the projectile, whch thrust may for purposes of analysis be regarded as a direct action force derived from the explosive gases, This direct action force obviously augments the forward momentum of the projectile, thereby increasing its penetrating ability.

Immediately after or concurrently with the direct action hammer blow illustrated in Fig. 1, the fuse 20 is blown out bodily from the projectile, producing the situation illustrated in Fig. 2. Here, due to the rearward expulsion of the fuse and the gases of the explosive charge, a reaction force is produced, just as in the case of the recoil of a gun, which also drives the projectile forwardly as indicated by the arrows. Hence it is seen that the explosive force of the shell charge is utilized to produce a direct action force and two reaction forces acting jointly to drive the projectile forward.

The increase of momentum of the projectile due to the impulsive forces of the hammer blow by part 25, the reaction from the expulsion of the fuse, and the reaction of the blow-out of the explosive gases can be expressed by the equation:

Where MV is the augmentation of the momentum of the projectile;

are the momenta of the hammer, fuse, and explosive charge respectively; and e1, e2, 63 represent the efficiency of these factors.

Fragmentation experiments have shown that high explosive charges can propel shell fragments with a velocity of several thousand feet per second. Thus, while the masses of the three factors in the above equation must always be less than that of the projectile, the velocities can materially exceed that of the projectile. Hence by suitable design of the projectile and proper choice of explosive charge, following the teaching of the invention, the combined effect of these three aiding factors can materially augment the penetrating ability of the projectile.

Although only a single embodiment of this invention has been illustrated and described, it is to be expressly understood that the invention is not limited thereto, but that various changes and adaptations may be made therein. For example, the projectile may be a so-called deck-piercing bomb having a strong head portion and body, and in lieu of a screwed-in base-plug, a slidable in ertia member fitted into the rear part of'the projectile body may be employed. Changes in the design and arrangement of parts may also be made without departure from the spirit and scope of the invention, as will now be understood by those skilled in the art. For a definition of the limits of the invention, reference will be had primarily to the appended claims.

Without further analysis, it will be evident that the present invention provides simple, practical, and efiective means for improving the armorpiercing ability of projectiles of the class described.

I claim:

1. An armor piercing projectile having an integral hollow body made of hard metal, such as alloy steel, comprising a massive hardened head and a hollow cylindrical portion having an axial main cavity of substantially uniform diameter, a piston member mounted for forward movement therein and dividing said cavity into two substantially equal chambers, an expellable plug fittedin the base end of said body and closing said cavity, a charge of detonating explosive positioned intermediate said piston member and said plug, and means in said plug for detonating said explosive charge on impact of said projectile with a highly resistant target.

2. An armor piercing projectile having a monoblock hollow cylindrical body made of alloy steel comprising a massive head portion tempered for hardness and rigidity and a hollow shell integral therewith, tempered for toughness and elasticity and having an axial cavity of substantially uniform bore formed from the base end, a piston mounted for forward movement in said cavity so as to divide the cavity into two chambers, an expellable plug closing said cavity at the base end, a charge of high explosive positioned in the chamber between said plug and said piston, and means carried by said plug for detonating said explosive charge on impact of the projectile With a resistant target.

3. An armor piercing projectile having an integral main portion made of strong metal comprising a massive hardened head and an elastic hollow cylindrical body having a cylindrical cavity of substantially uniform diameter formed from the base end, a piston member mounted for forward movement within and dividing said cavity into two chambers, a closure member adapted to close said cavity at the rear end thereof, a charge of high explosive contained in the chamber between said piston member and said closure member, and means in exploding relation to said charge for detonating said charge on impact of the projectile with a target.

4. In armor piercing projectiles provided with explosive means for augmenting the velocity of the projectile upon impact with a resistant target, a monoblock integral alloy steel body portion comprising a massive hardened head and an elastic hollow cylindrical shell having a cavity of substantially uniform bore formed from the base end thereof, a solid massive piston mounted near the middle of said cavity for forward movement therein and dividing said cavity into two chambers, an expellable plug member closing said cavity at the base, a detonating high explosive charge in the chamber between said piston and said plug, and means for detonating said charge upon impact of said head with a resistant target, thereby generating direct and reactive forces augmenting the forward velocity of said body portion.

5. In a projectile, in combination, a main body having an ogival head integral with a cylindrical shell having a concentric cylindrical cavity formed from the base end, a rearwardly ejectable base closure member for said cavity, and means for augmenting the penetration of said body into a target including a piston mounted inside said cylindrical shell dividing said cavity into two chambers, a charge of high explosive in the rearward of the two chambers, and means within said closure member for detonating said charge on impact with a target, thereby causing said piston to deliver a forwardly acting blow to said head.

6. In a projectile, in combination, a main body comprising an ogival head and an integral cylindrical shell having a concentric cylindrical cavity extending from the base end, a rearwardly ejectable base closure member for said cavity, and means for augmenting the penetration of said body into a target including a piston mounted inside said cylindrical cavity so as to divide said cavity into two chambers, a charge of explosive in the rearward of the two chambers, and means positioned rearwardly of said charge for eimloding said charge upon impact of the projectile with a target.

7. A projectile comprising an ogival head and an integral hollow cylindrical body and having a cylindrical cavity formed from the base end and walls of substantially uniform thickness, a rearwardly ejectable closure member for said cavity, a piston mounted for forward movement in said cavity and dividing said cavity into two chambers, a charge of high explosive in the rearward chamber, and means positioned rearwardly of said charge for detonating said charge on impact of the projectile with a target.

8. In a projectile having a rotating band, in combination with a pointed head and a hollow cylindrical body having a cavity formed from the base end and walls of substantially uniform thickness, of a rotating band of soft metal bonded to the outside perimeter of said Walls, a rearwardly ejectable closure member for said cavity, a piston mounted for forward movement in said cavity, a charge of high explosive positioned rearwardly of said piston, and means for detonating said charge positioned rearwardly thereof.

9. A projectile comprising, in combination, a pointed head and an integral cylindrical body having a concentric cylindrical cavity, a movable piston mounted in and dividing said cavity into two cavities, means positively holding said piston against movement until the projectile hits a target, a charge of high explosive rearward of said piston, a rearwardly ejectable closure for said cavity, and detonating means for said charge carried by said closure member.

HARRY J. NICHOLS.

REFERENCE S CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,146,484 Dunwoody July 13, 1915 672,827 'Gathmann Apr. 23, 1901 2,091,635 Hayden Aug. 31, 1937 2,310,915 Hurley Feb. 9, 1943 

